Z2DA--542-23-201 | Replace Roofs Building 69 and 139 | NCO 4 Construction East (VA-26-00047303)

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Replace Roofs Building 69 and 139
Project No. 542-23-201, Solicitation 36C24426B0010
Amendment No. 002

Additional Contractor Questions and VA responses (bold).

Please provide a copy of the phase 1 asbestos survey/report (or any applicable hazardous materials report) covering the scope of work for this project. This can be found in the Design Narrative - Appendix DÂ

The taper drawing on sheet A-105 shows a Y-panel start at the roof drain with a starting thickness of 1½-inch (R-8.6). The taper drawing on sheet A-110 shows an X-panel start at the roof drain with a starting thickness of ½-inch (
Please provide a typical roof system detail for the shingle assembly similar to that shown on Detail 2/A-503 for the low-slope assembly.

Where does the composite nail base specified in Section 07 22 00, paragraph 2.4.D get installed? Please specify the thickness required. This was taken from the VA.TIL specs we had left this in the specifications for the penthouse shingled roof. Â VA requires adherence with the specification.

For the skylight removal on Building 139, Details 2 & 3/S-104 appear to indicate that a new raised deck will be installed approximately 14-inches above the existing roof. This would create a base flashing condition. Sheet A-107 does not show this raised area. Will the new structural deck at the skylight removal be flush with the existing deck, or will it be raised? If raised, please provide details showing the roof flashing and termination conditions at this area. The design intent is for the roof deck infill to be placed on the existing curbs and be raised as shown in the detail on S104. This allows for the 6" cold form to be installed to support the new ceiling within these skylights. The flashing detail is similar to Detail 4 found on sheet A503.

Section 07 31 13, paragraph 2.1.A refers to Section 09 06 00 for the shingle Basis of Design. The 09 06 00 specification states the shingle size, shape, and manufacturer are to be selected. Please provide a basis of design for the shingles. Refer to section 073113 2.2, for requirements.

Will snow guards be required on the shingle roof? There are currently snow guards installed in the shingle roof only above the penthouse doorway but not the entire perimeter. VA requires to maintain snow guards in that location.  These are listed in 073113 2.7

Section 07 52 16.11, paragraph 2.3.C.2: are bio-based SBS modified bitumen products applicable to this project? Yes, cold applied membrane adhesives are required to have bio-based content. Refer to 075216 2.5 C and D
Referring to Detail 3/A-503, the replacement fascia appears to be a unique custom prefabricated item. Please provide a manufacturer basis of design for this fascia. Include material type and size/thickness. Also, please provide attachment requirements and details. Match existing adjacent trim in materiality and method of connection.Â

Referring to Detail 3/A-503, the shingles and roof felt appear to be installed over some sort of insulation and a wood starter block. Is this insulation currently in-place? What substrate will the shingles be nailed to? Nail base (refer to question 4). Note that this is not a vented product consider a vented nailboard (see Hunter Cool-vent as an example).Â

Refer to the phasing plan for Building 139 (Sheet A-108). Phases 03, 04, and 05 entail installing and flashing new HVAC units prior to installing the new roof assembly under phases 06, 07, and 08. The new roofing and flashing assemblies (SBS modified bitumen) are incompatible with the existing EPDM assemblies. The new flashing installed during phases 03, 04, and 05 cannot be properly sealed to the existing EPDM. Can Phases 03, 04, and 05 be combined with phases 06, 07, and 08? If not, please provide tie-in details between the new modified system and the existing EPDM system. The specified final membrane flashings for the modified bitumen roof system should be installed during phase 06, 07 and 08. Install temporary watertight seals compatible with existing EPDM roofing for work in phases 03, 04 and 05. Unless otherwise noted, prep surrounding existing roofing with membrane cleaner and primer, and install EPDM membrane patch material (typical peel and stick patch roll with pressure sensitive adhesive backing and release liner) to make curbs weathertight until reroofing phase work begins.

Refer to the phasing plan for Building 139 (Sheet A-108). Which trade provides and installs the penetration housings listed under Phases 03, 04, and 05? Typically a mechanical contractor provides/installs and the roofing contractor flashes to the roof, but decision falls on prime contractor and specifications.

Advise what are the ICRA Levels in the areas below the roof level where items are to be removed and decking repairs are required. For example, where skylights and penetrations are to be removed. Refer to Appendix E of the Design Narrative Â

Is the use of temporary plastic wall panels (such as STARC panels) acceptable to meet ICRA requirements? ICRA barrier approval will come after formal submittal process to awarded contractor.
Roof plans indicate providing roof curb extensions. Please advise if sizes of curbs or model numbers of existing equipment can be provided. Please clarify required height of extension. Refer to General Notes on M101. Additional info requested was "if possible" - I do not have that information at this minute, and I have not yet received any further detail. But the question regarding the curbs is covered in the General Notes. If I get anything further today I will send it but this response should be satisfactory.Â
Confirm there are no existing asbestos or hazardous materials to be removed. This can be found in the Design Narrative - Appendix DÂ

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